Manufacture and repair of incandescent electric lamps.



F. FA'NTA. MANUFACTURE AND REPAIR OF INCANDESGENT ELECTRIC LAMPS.

(Application filed May 26, 1900.)

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UNITED STATES- PATENT OFFICE.

FERDINAND FANTA, OF LONDON, ENGLAND.

MANUFACTURE AND REPAIR OF INCANDESCENT ELECTRIC LAMPS.

' SPECIFICATION forming part of Letters Patent No. 683,5 dated October 1, 1901.

Application filed May 26, 1900. Serial No- 1s,154. (No specimens.)

To all whom, it may concern.-

Be it known that I, FERDINAND FANTA, a subject of the Queen of Great Britain and Ireland, residing at London, England, have invented a new and useful Improvement in and Relating to the Manufacture and Repair of Incandescent Electric Lamps, (for which I have made application in Great Britain under No. 21,966, hearing date November 2, 1899; in France under No. 288,125, bearing date May 2,1900, andin Belgium under No. 118,170, bearing date May 2, 1900,) of which the folowing is a specification.

The object of this invention is a mode of treatment for increasing the life of electricinn candescent lamps by renewing or regenerating the incandescent filaments of the same when their efficiency has become too low while fixed in their sockets and leads and in the globe in which they are to be used as lamps, thus reducing the original outlay or cost of those lamps to a considerable extent.

As is well known the passage of current through the filament in use as a lamp results in a part of such filament volatilizing, the particles of carbon thus volatilized attaching to the inner surface of the bulb, whereby the same is obscured, while the resistance of the filament is increased considerably. The lighting efficiency of the lamp thus decreasing rapidly, the same has soon to be discarded altogether. I am aware that attempts have been made to use the bulbs of such burnedout or spent lamps over again; but in all instances the inventors have suggested the withdrawal of the old filament. It is obvious that this is a costly and in most instances more difficult process than the manufacture of the original lamp, and the principle is, moreover, at fault, as shown by the following considerations, which I have ascertained experiment-ally.

It has hitherto been believed that the whole body of the filament volatilizes orburns away and loses in value in regard to its transmitting and lighting efficiency and that the core, so to say, of the filament is destroyed; but I find that this is not the case, but, on the contrary, that the core or body of such filament is after having been in use for several hundred hours in a far better condition than when originally insertedinto the lamp. This is accounted for by the fact that the original carbonizing process which the filament has to undergo before its insertion into the bulb is performed too rapidly, and, further, that the process known as the reinforcing or flashing of the filament is carried out under unsatisfactory conditions, and these conditions are in most instances entirely at variance with those under which such filament comes into use in the finished lamp. The result of this is that when the filament is used, as it is in actual practice, in a more or less perfect vacuum, and owing to the atmospheric air (which is still retained or imprisoned in the pores of the filament) becoming available for combustion the outer coating of carbon of such filament slowly combines with the same, and the O0 vapors thus formed deposit on the inner surface of the glass bulb, which acts in the fashion of a condenser. In order to again render serviceable an electric incandescent lamp which has reached the above-described stage, it is therefore indispensable, first, to free the bulb of such carbon deposit, and, secondly, to redeposit carbon on the partly burned or spent filament. A

The object of this invention is to accomplish both these operations without removing the filament from the lamp, and consequently withoutinterfering with the bulb, seal, or the capping of the lamp.

For carrying out the invention I first of all remove or cut away the small protruding point of glass formed on the bulb of the lamp as originally made, when the tube by which the vacuum has been made therein is removed by means of the blowpipe, and I fix onto the bulb instead of the point just broken off a small glass tube from four to six inches long. I thereafter heat the 'bulb outwardly and preferably locally by a flame applied successively over the surface to such a degreeas may be necessary to burn the carbon deposited on its inner surface, and this operation is facilitated and rendered practicable at temperatu res not injurious to the integrity of the glass and the preservation of the capping and the filament by my causing previously-heated air to circulate freely in the bulb while simultaneously-drawing off the gases resulting from the combustion by means of a pump or of any other aspirating apparatus.

The annexed drawings show in Figure l, as a vertical section, a practicable device for effecting the above circulation. Fig. 2 shows a diagrammatic arrangement of a number of lamps in position for treatment, and Fig. 3 shows diagrammatically an arrangement of circuits and resistances during regeneration.

The tube a of the globe, which I use for the above purpose, is fixed gas-tight by a stuffingbox b and gland b in a casing c and carries an inner tube 2', the extremity of which is long enough to reach the part of the bulb diametrically opposite to the portion of the bulb into which the outer tube a is jointed. The inner tube 1', which is also fixed gas-tight in a lower stuffing-box e, is then used for the introduction of the atmospheric air from the flangeopeningf or h, controlled by a two-Way cock at, while the outertube is connected to a pump through the side orifice g, also controlled by a cock, and provides means for withdrawing the gases resulting from the combustion of the carbon deposit. After a short period of application of this cleansing process the glass of the bulb appears quite clear and free of the carbon. The bulb is now ready, and the process of depositing carbon'on the filament can be proceeded with. For this purpose, having created as perfect a vacuum as possiblein the bulb, I introduce into the bulb by mechanical circulation under pressure controllable as to required reduced pressure in bulb a gaseous hydrocarbon (as gasified liquid hydrocarbon or, more conveniently, purified coal-gas) with an admixture of a certain quantity of free atmospheric air, the proportion or percentage of which'varies in accordance with the voltage and the candle-power of the filament and the condition of the vacuum in the lamp to be treated,as stated hereunder. I then pass the electric current through the filament.

The introduction of the gaseous admixture can be efiected by means of the above-referredto inner tube 7; by one of the alternative passages f and h, controlled by a two-way cook 61, and the withdrawal of the gases resulting from the slow combustion brought about by the incandescence of the filament caused by r the passage of the electric current is efiected by means of the pump through the side exit g, the pressure of the gaseous mixture in the bulb .being carefully regulated and maintained by means of adequate pressure-regulating valves or other automatic devices, it being essential to the success of the process that such pressure be adjusted to the condition of the filament in relation to the voltage of current and the candle-power required from the filament, as also to the size of the containing-bulb, as more particularly defined hereunder. As a result of this process carbon deposits on the filament, and it is obvious the resistance of the same diminishes, while the candle-power increases. Since, on the other hand, the object is to restore the carbon filament to its original smaller resist-v ance and higher candle-power, I begin my operation with a variable resistance It, Fig. 3, inserted in the main regenerating-circuit Z, and I gradually increase this resistance simultaneously with the deposit of carbon upon the filament to compensate for the increasing section and reduced resistance of the filament and use a photometer 19, Fig. 3, for the purpose of standardizing the required lighting efficiency of the reinforced filament in comparison with a standard lamp or source of light m on a separate constant circuit 92 and with a required voltage of current on the regenerating-circuit Z, maintained at a constant calculated volt-age by the variable resistances 7c. Istop the operation when the voltage and'the candle-power indicated by the instruments have reached the desired pointviz., when the resistance, and consequently the candle-power of the filament have been brought back to their former value in the original lamp or to a predetermined or required standardized value. Allowance should, however, be made for the fact that the resistance of the filament when in vacuum is less than that of the filament immersed in the gaseous mixture, and consequently the normal voltage of the finished lamp when sealed in cacao will be considerably lower than that appearing during the time of finishing or flashing the same in the gaseous mixture and while the lamp is unsealedi. 2., the voltage of the regenerating-circuit Z, Fig. 3, is at a much higher and calculated voltage than the voltage of the ultimate working circuit on which the lamp is designed to be eventually used when sealed in vacuo. \Vhen the process has been completed to this point, the bulb is exhausted and sealed in the usual well-known manner.

I find that the proportion of atmospheric air of the gaseous mixture, which is important to prevent deposit of carbon on the glass, should vary from three to ten per centum, according to the nature or condition of the filament to be flashed, the percentage of the air being smaller for filaments of low candle-power than forfilaments of higher candle-poweri. e. for a filament of sixteen candle-power a percentage of five of air will be suitable for a uniform filament; but with a burned filament of irregular section, of poor condition, the percentage of-air must be kept at the above lowest value until the filament has been reinforced at its weakest parts, when the percentage of air may be increased. The quantity of air used is also dependent on the efficiency of the pump used, viz: The proportion of air forming part of the gaseous mixture maybe smallerwhen powerful pumps (pumps which are capable of drawing otl' large bulk of gases) than when less powerful section of the filament, and the condition of the latter. Filaments of poor efficiency and those of high resistance require more pressure than those of better efficiency and those of low resistance-as, for instance, a partlyburned or irregular filament of high resistance in whole or in part must be regenerated at first at the highest of the above pressures, and as the filament becomes uniform the pressure may be reduced and the deposit of carbon thus diminished by reduction of pressure up to the point of above lowest pressure when nearing the point of standard or required section or resistance.-

The above variations of pressure and percentage of air must be left to the'skill and observation of the operative upon the above generally-indicated principles to prevent burning or cleflagration of a worn, irregular, or poor filament, as in the matter of repair no two are alike in condition when regeneration is first commenced. The same filament will require less pressure in the bulb when treated in a large than in a smaller bulb in order to give better advantage to the mechanical pressure of supply of the gas (which is much higher than the above pressures used in the bulb) to produce a more vigorous circulation through the larger bulb than is necessary in the smaller bulb. I further wish it to be understood that since the present invention shows a method to flash the filament in the actual bulb in which it is to be used, owing to my preventing sooty carbonaceous matter from being formed and depositing on the containers during the-flashing process, (owing to my using an appropriate percentage of atmospheric air,) this process would advantageously replace the mode of finishing or flashing the filaments previously to their insertion into the bulb of the lamp, and also I wish it to be understood that the simultaneous use of the photometer as described herein during flashing and before the sealing of the bulb provides means not onlyrof ascertaining and adjusting the efficiency of the filament most accurately, but also (and this is most important) to reduce to a very large extent, if not to do away altogether with, the large percentage of odd voltages of the lamps as now resulting from the mode of manufacture commonly used by incandescent-electric-lamp makers.

Having now described this invention, what I claim, and desire to secure by Letters Patent, is

1. A process for the regeneration and reinforcement of the carbon filaments of. incandescent electric lamps, while fixed in Sit Lb in the lamp-globes in which they are to be eventually used, consisting in making access to the upper part of the globe; removing the air from the globe; mixing air and a hydrocarbon gas, within the limits of variable proportion as specified; circulating mechanically under controlled pressure the said mixed gases through the said globe, from one end to the other; passing an electric current through said filament while said circulation is in progress; stopping the current when filament is standardized; exhausting the residual hydrocarbon gas from the globe without admission of the atmosphere; and finally sealing the globe, substantially as specified.

2. In' a process for the regeneration and reinforcement of the carbon filaments of incandescent electric lamps, while fixed m sitzt in the lamp-globes in which they are to be used, continuously circulating a mixture of air and hydrocarbon through the said globe, While an electric current is passing through the said filament, substantially as specified.

3; In a process for the regeneration and reinforcement of the carbon filaments of used incandescent electric lamps, circulating into the said globe previously-heated air,and withdrawing therefrom products of combustion, simultaneously with the application of moderate external heat to clean and prepare the globe of the lamp for the regeneration and reinforcement of the filament, substantially as specified.

4. In a process for the regeneration and re inforcement of the carbon filaments of incandescent electric lamps in situ in the lamps in which they are eventually to be used, regulating mechanically the pressure and the proportions of the mixed hydrocarbon gas and air, while the same is circulating through the globes of the said lamps, to suit the condition and candle-power of the filament, and the size of the globe, substantially as specified.

5. In a process for the regeneration and reinforcement of the carbon filaments of incandescent electric lamps, the mode of standardizing the filament in situ in the globe in which it is to be eventually used, before sealing the same, consisting in passing a mechan ically circulated and controlled stream of mixed air and hydrocarbon gas uniformly over said filament, (in order to avoid an obscuring deposit on inside of globe and to avoid burning a Weak or poor filament); passing an electric current, of predetermined excess value above that at which the lamp is to be worked in cacao, through said filament in said mixed vapor; controlling said current at desired voltage by variable added resistances,

to compensate for the resistance of reinforcglobe, and without disturbance of filament :0 ing filament; estimating by the photometer connections, to form a complete standardized the required incandescence of the filamentunlamp, ready for nse,snbstantially as specified. der said controlled and definite electric cnr- In Witness whereof I have hereunto set my 5 rent; determining the cessation of the reinhand in presence of two witnesses.

forcing process by photometric test; exhaust- FERDINAND FAN'IA.

ing the residual hydrocarbon vapor from the globe; and the sealing of the globe in situ \Vitnesses RICHARD A. HQFFMANN,

without admission of the atmosphere to the 1 WILLIAM CORNHILL. 

